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<h2><span class="refentrytitle">Function template copy</span></h2>
<p>boost::compute::copy</p>
</div>
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../boost_compute/reference.html#header.boost.compute.algorithm.copy_hpp" title="Header &lt;boost/compute/algorithm/copy.hpp&gt;">boost/compute/algorithm/copy.hpp</a>&gt;

</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> InputIterator<span class="special">,</span> <span class="keyword">typename</span> OutputIterator<span class="special">&gt;</span> 
  <span class="identifier">OutputIterator</span> 
  <span class="identifier">copy</span><span class="special">(</span><span class="identifier">InputIterator</span> first<span class="special">,</span> <span class="identifier">InputIterator</span> last<span class="special">,</span> <span class="identifier">OutputIterator</span> result<span class="special">,</span> 
       <span class="identifier">command_queue</span> <span class="special">&amp;</span> queue <span class="special">=</span> <span class="identifier">system</span><span class="special">::</span><span class="identifier">default_queue</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> 
       <span class="keyword">const</span> <a class="link" href="wait_list.html" title="Class wait_list">wait_list</a> <span class="special">&amp;</span> events <span class="special">=</span> <a class="link" href="wait_list.html" title="Class wait_list">wait_list</a><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="idm46604988709360"></a><h2>Description</h2>
<p>Copies the values in the range [<code class="computeroutput">first</code>, <code class="computeroutput">last</code>) to the range beginning at <code class="computeroutput">result</code>.</p>
<p>The generic copy() function can be used for a variety of data transfer tasks and provides a standard interface to the following OpenCL functions:</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p><code class="computeroutput">clEnqueueReadBuffer()</code> </p></li>
<li class="listitem"><p><code class="computeroutput">clEnqueueWriteBuffer()</code> </p></li>
<li class="listitem"><p><code class="computeroutput">clEnqueueCopyBuffer()</code> </p></li>
</ul></div>
<p>
Unlike the aforementioned OpenCL functions, copy() will also work with non-contiguous data-structures (e.g. <code class="computeroutput">std::list&lt;T&gt;</code>) as well as with "fancy" iterators (e.g. <code class="computeroutput"><a class="link" href="transform_iterator.html" title="Class template transform_iterator">transform_iterator</a></code>).</p>
<p>

For example, to copy an array of <code class="computeroutput">int</code> values on the host to a vector on the device: </p>
<pre class="programlisting"><span class="comment">// array on the host</span>
<span class="keyword">int</span> <span class="identifier">data</span><span class="special">[</span><span class="special">]</span> <span class="special">=</span> <span class="special">{</span> <span class="number">1</span><span class="special">,</span> <span class="number">2</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="number">4</span> <span class="special">}</span><span class="special">;</span>

<span class="comment">// vector on the device</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">vec</span><span class="special">(</span><span class="number">4</span><span class="special">,</span> <span class="identifier">context</span><span class="special">)</span><span class="special">;</span>

<span class="comment">// copy values to the device vector</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">::</span><span class="identifier">copy</span><span class="special">(</span><span class="identifier">data</span><span class="special">,</span> <span class="identifier">data</span> <span class="special">+</span> <span class="number">4</span><span class="special">,</span> <span class="identifier">vec</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">queue</span><span class="special">)</span><span class="special">;</span>
</pre>
<p>The copy algorithm can also be used with standard containers such as <code class="computeroutput">std::vector&lt;T&gt;</code>: </p>
<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">host_vector</span> <span class="special">=</span> <span class="special">...</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">device_vector</span> <span class="special">=</span> <span class="special">...</span>

<span class="comment">// copy from the host to the device</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">::</span><span class="identifier">copy</span><span class="special">(</span>
    <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">end</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">queue</span>
<span class="special">)</span><span class="special">;</span>

<span class="comment">// copy from the device to the host</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">::</span><span class="identifier">copy</span><span class="special">(</span>
    <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">end</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">queue</span>
<span class="special">)</span><span class="special">;</span>
</pre>
<p>Space complexity: \Omega(1)</p>
<p><span class="bold"><strong>See Also:</strong></span></p>
<p>copy_n(), copy_if(), copy_async() </p>
<p>
</p>
<p>
</p>
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<td><p><span class="term">Parameters:</span></p></td>
<td><div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
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<td><p><span class="term"><code class="computeroutput">first</code></span></p></td>
<td><p>first element in the range to copy </p></td>
</tr>
<tr>
<td><p><span class="term"><code class="computeroutput">last</code></span></p></td>
<td><p>last element in the range to copy </p></td>
</tr>
<tr>
<td><p><span class="term"><code class="computeroutput">queue</code></span></p></td>
<td><p>command queue to perform the operation</p></td>
</tr>
<tr>
<td><p><span class="term"><code class="computeroutput">result</code></span></p></td>
<td><p>first element in the result range </p></td>
</tr>
</tbody>
</table></div></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p><code class="computeroutput">OutputIterator</code> to the end of the result range</p></td>
</tr>
</tbody>
</table></div>
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<td align="right"><div class="copyright-footer">Copyright © 2013, 2014 Kyle Lutz<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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